Considering the problems of uncertainties and external disturbances during the operation of high-speed train (HST), a fixed-time non-singular terminal sliding mode control method based on the distributed observer is proposed to track a given target speed quickly, accurately, and stably. First, the multi-agent model of HST is constructed by according to the force situation during the actual operation of the train. Secondly, the terminal sliding mode surface is selected and combined with the double power reaching law to design the fixed-time terminal sliding mode controller for the leader vehicle. Since there is no direct communication between some of the follower vehicles and the leader vehicle in HST, the position and speed of the leader vehicle cannot be obtained. A distributed fixed-time observer is designed to observe the state information of the leader vehicle. While, the non-singular terminal sliding mode surface is used to design the fixed-time non-singular terminal sliding mode controller for the follower vehicles. By Lyapunov stability theory, it proves that the designed observer and controller can be stabilized in a fixed time, respectively. Finally, the simulation is carried out with the parameters of CRH-type trains. under the condition of introducing external disturbances. The method is utilized to compare with the sliding-mode consistency method. The results show that the proposed algorithm can enable the follower vehicles to track the target velocity profile quickly and accurately with the velocity error within -2×10-6~2×10-6 m/s, and with strong robustness compared with the sliding mode consistency method.